In a nutshell: stay away from ionos.com
Ionos.com used to be called 1and1.com. I have/had been with 1and1.com for more than 20 years and happy with the service.
My satisfaction with them has changed drastically in the last year or so, as they attempt to nickle and dime their own customers to death. I now consider them grifters who everyone should avoid like the plague.
Here are a few examples.
Every time I log in to ionos.com they ask if I want to switch to ionos.ca. Makes sense as I live in Canada, so I moved one of my domains. You’d think this would be easy, that I could just ask them to move my stuff over. Not even close. Instead they treat me like a non-customer and force me to re-register any domain I move.
Another trick they use is to artificially tie services together to make cancelling difficult. I had a cloud server with them, and an SSL certificate. These two services had nothing to do with each other (I managed the server myself), yet I could not cancel the server when I no longer needed it without also cancelling the certificate.
Managing your account sucks quite bad, the website is apparently designed primarily to make it easier for them to sneak in extra charges. I have an account at namecheap.com and find their interface easier to use. Mostly easy (some things a little non-intuitive but I figured them out), certainly better than Ionos.
I don’t know yet if customer service is better at NameCheap, so far no need for it as I’ve been able to figure out how to do things myself pretty quickly. Ionos.com’s site had limitations so I had to call them, usually waiting for 15 minutes or more on hold, and often having my calls randomly dropped, sometimes in the middle of a conversation. Support personal varied in competence and politeness quite a bit. I’m always polite on the phone (because I’m not stupid) but my impression sometimes was the guy on the other end (rare or no female support in my experience) was a bit of a jerk.
I had paid for SSL certificates with Ionos, but when I moved a domain to NameCheap Ionos revoked the cert. The cert I had paid for. Pretty scummy move on their part.
In short, after more than 20 years with them I only have two words left for ionos.com: “fuck off”.